1
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
List-I List-II
(a) MI of the rod (length L, Mass M, about an axis $$\bot$$ to the rod passing through the midpoint) (i) $$8M{L^2}/3$$
(b) MI of the rod (length L, Mass 2M, about an axis $$\bot$$ to the rod passing through one of its end) (ii) $$M{L^2}/3$$
(c) MI of the rod (length 2L, Mass M, about an axis $$\bot$$ to the rod passing through its midpoint) (iii) $$M{L^2}/12$$
(d) MI of the rod (Length 2L, Mass 2M, about an axis $$\bot$$ to the rod passing through one of its end) (iv) $$2M{L^2}/3$$

Choose the correct answer from the options given below:
A
(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
B
(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
C
(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
D
(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
2
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
The figure shows two solid discs with radius R and r respectively. If mass per unit area is same for both, what is the ratio of MI of bigger disc around axis AB (Which is $$\bot$$ to the plane of the disc and passing through its centre) of MI of smaller disc around one of its diameters lying on its plane? Given 'M' is the mass of the larger disc. (MI stands for moment of inertia)

A
R2 : r2
B
2r4 : R4
C
2R2 : r2
D
2R4 : r4
3
JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Moment of inertia of a circular disc of mass 'M' and radius 'R' about X, Y axes (passing through its plane) and Z-axis which is perpendicular to its plane were found to be Ix, Iy and Iz respectively. The respectively radii of gyration about all the three axes will be the same.

Reason R : A rigid body making rotational motion has fixed mass and shape. In the light of the above statements, choose the most appropriate answer from the options given below :
A
Both A and R are correct but R is NOT the correct explanation of A.
B
A is not correct but R is correct.
C
A is correct but R is not correct.
D
Both A and R are correct and R is the correct explanation of A.
4
JEE Main 2021 (Online) 22th July Evening Shift
+4
-1
Consider a situation in which a ring, a solid cylinder and a solid sphere roll down on the same inclined plane without slipping. Assume that they start rolling from rest and having identical diameter.

The correct statement for this situation is
A
All of them will have same velocity.
B
The ring has greatest and the cylinder has the least velocity of the centre of mass at the bottom of the inclined plane.
C
The sphere has the greatest and the ring has the least velocity of the centre of mass at the bottom of the inclined plane.
D
The cylinder has the greatest and the sphere has the least velocity of the centre of mass at the bottom of the inclined plane.
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